package com.wm.file.util;

import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * @ClassName: ZipUtils
 * @Description:
 * @Author: xiaomage
 * @Date: 2021-08-06 20:33
 **/
@Component
@Slf4j
public class ZipUtils {
    private static final int BUFFER_SIZE = 2 * 1024;

    /**
     * 压缩成ZIP 方法
     * @param srcDir 压缩文件夹路径
     * @param out              压缩文件输出流
     * @param KeepDirStructure 是否保留原来的目录结构,true:保留目录结构;
     *                         false:所有文件跑到压缩包根目录下(注意：不保留目录结构可能会出现同名文件,会压缩失败)
     * @throws RuntimeException 压缩失败会抛出运行时异常
     */
    public static void toZip(String srcDir, OutputStream out, boolean KeepDirStructure)
            throws RuntimeException {
        log.info("正在压缩文件。。。");
        long start = System.currentTimeMillis();
        ZipOutputStream zos = null;
        try {
            zos = new ZipOutputStream(out);
            File sourceFile = new File(srcDir);
            compress(sourceFile, zos, sourceFile.getName(), KeepDirStructure);
            long end = System.currentTimeMillis();
            log.info("压缩完成，耗时：" + (end - start) + " ms");
        } catch (Exception e) {
            throw new RuntimeException("zip error from ZipUtils", e);
        } finally {
            if (zos != null) {
                try {
                    zos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }

    /**
     * 压缩成ZIP 方法     * @param srcFiles 需要压缩的文件列表
     *
     * @param out 压缩文件输出流
     * @throws RuntimeException 压缩失败会抛出运行时异常
     */
    public static void toZip(List<File> srcFiles, OutputStream out) throws RuntimeException {
        long start = System.currentTimeMillis();
        ZipOutputStream zos = null;
        try {
            zos = new ZipOutputStream(out);
            for (File srcFile : srcFiles) {
                byte[] buf = new byte[BUFFER_SIZE];
                zos.putNextEntry(new ZipEntry(srcFile.getName()));
                int len;
                FileInputStream in = new FileInputStream(srcFile);
                while ((len = in.read(buf)) != -1) {
                    zos.write(buf, 0, len);
                }
                zos.closeEntry();
                in.close();
            }
            long end = System.currentTimeMillis();
            System.out.println("压缩完成，耗时：" + (end - start) + " ms");
        } catch (Exception e) {
            throw new RuntimeException("zip error from ZipUtils", e);
        } finally {
            if (zos != null) {
                try {
                    zos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }


    /**
     * 递归压缩方法
     *
     * @param sourceFile       源文件
     * @param zos              zip输出流
     * @param name             压缩后的名称
     * @param KeepDirStructure 是否保留原来的目录结构,true:保留目录结构;
     *                         false:所有文件跑到压缩包根目录下(注意：不保留目录结构可能会出现同名文件,会压缩失败)
     * @throws Exception
     */
    private static void compress(File sourceFile, ZipOutputStream zos, String name,
                                 boolean KeepDirStructure) throws Exception {
        byte[] buf = new byte[BUFFER_SIZE];
        if (sourceFile.isFile()) {
            // 向zip输出流中添加一个zip实体，构造器中name为zip实体的文件的名字
            zos.putNextEntry(new ZipEntry(name));
            // copy文件到zip输出流中
            int len;
            FileInputStream in = new FileInputStream(sourceFile);
            while ((len = in.read(buf)) != -1) {
                zos.write(buf, 0, len);
            }
            // Complete the entry
            zos.closeEntry();
            in.close();
        } else {
            //是文件夹
            File[] listFiles = sourceFile.listFiles();
            if (listFiles == null || listFiles.length == 0) {
                // 需要保留原来的文件结构时,需要对空文件夹进行处理
                if (KeepDirStructure) {
                    // 空文件夹的处理
                    zos.putNextEntry(new ZipEntry(name + "/"));
                    // 没有文件，不需要文件的copy
                    zos.closeEntry();
                }
            } else {
                for (File file : listFiles) {
                    // 判断是否需要保留原来的文件结构
                    if (KeepDirStructure) {
                        // 注意：file.getName()前面需要带上父文件夹的名字加一斜杠,
                        // 不然最后压缩包中就不能保留原来的文件结构,即：所有文件都跑到压缩包根目录下了
                        compress(file, zos, name + "/" + file.getName(), KeepDirStructure);
                    } else {
                        compress(file, zos, file.getName(), KeepDirStructure);
                    }

                }
            }
        }
    }

    /**
     * 向浏览器发送zip包
     *
     * @param response
     */
    public static void sendZip(HttpServletResponse response, File zipFile) {
        log.info("正在发送zip包");
        OutputStream outputStream = null;
        BufferedInputStream fis = null;
        try {
            // 以流的形式下载文件。
            fis = new BufferedInputStream(new FileInputStream(zipFile.getPath()));
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            // 清空response
            response.reset();
            outputStream = new BufferedOutputStream(response.getOutputStream());
            response.setContentType("application/octet-stream");
            response.setHeader("Content-Disposition", "attachment;filename=" + new String(zipFile.getName().getBytes("UTF-8"), "ISO-8859-1"));
            outputStream.write(buffer);
            outputStream.flush();
            log.info("发送成功。");
        } catch (Exception ex) {
            ex.printStackTrace();
        } finally {
            try {
                if (fis != null) {
                    fis.close();
                }
                if (outputStream != null) {
                    outputStream.close();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}
